GRAVITY SURVEYS IN HEAVY SAND DUNES
The paper discusses the problems involved in desert surveys under the headings of “Access” and “Correction of Gravity Data.” The types of sand formation are described. In planning a survey the importance of reconnaissance, aerial photographs, and the provision of suitable equipment are stressed. The advantages and disadvantages of motor transport, light aircraft, helicopters, and the operational procedures used with each are discussed. Terrain corrections are necessary on most stations and suggestions are given for their determination. The different densities of the dune sand and the “floor” introduce a problem in the determination of the Bouguer Correction. A method is given whereby close estimates of the sand thickness can be found by contouring on the “floor” or on minimum elevations. The resulting Bouguer values after computation are as regular as those found in areas of small elevational changes.